Apparatus for indicating changes in atmospheric pressure.



M. ALBRECHT.

APPARATUS FOR INDICATING CHANGES IN ATMOSPHERIC PRESSURE. APPLICATIONFILED MAY 27, 1914.

1,174,536. Patented Mar. 7, 1916.

'/IIIII/IIIIIII/IIIIIII' E I E I 2 z I A Wfhawm I I file/1%? i wi hMARTIN ALBRECHT, OF FRANKFORT-ON-TI-IE-MAIN, GERMANY.

APPARATUS FOR INDICATING CHANGES IN ATMOSPHERIC PRESSURE.

Specification of Letters Patent.

Patented Mar. '7, 1916.

Application filed May 27, 1914. Serial No. 841,339.

To all whom it may concern:

Be it known that I, MARTIN ALBREGHT,8I1

gineer, a citizen of the German Empire, re-

siding at Frankfort-on-the-Main, Hesse- Nassau, Prussia, Germany, haveinvented certain new and useful Improvements in Apparatus for IndicatingChanges in Atmospheric Pressure; and I hereby declare that the followingis a full, clear, and'exact description thereof, reference being had tothe accompanying drawings, which form part of this specification.

The present invention relates to apparatus for indicating changes in thegaseous condition of the atmosphere, for example, for indicating thepresence of fire-damp or choke-damp in mines.

It relates in particular to such systems in which a chamber covered witha porous plate is furnished with a pressure measuring device in theshape of a U-tube which is partly filled with liquid and can be madevery useful. These apparatus in themselves known are of only limited useand means are described below which renders this system considerablymore widely applicable. The one disadvantage of these apparatus consistsin the fact that the pressure effect produced by the diffusion chamberis only comparatively small, so that in mines or other applications itcannot be sufficiently well recognized.

According to the invention, the two limbs of the system of tubesconnected to the diffusion chamber are provided with a siphon tube, sothat it is only necessary for the liquid to rise up to the top of thesiphon tube in order for the rest of the liquid to run out.Consequently, the siphon tube acts as a multiplier for the measurement.The introduction of the siphon has yet a further ad vantage in thepresent case, viz. that the liquid no longer runs back when the increaseor decrease in pressure subsides and accordingly can be retained oneither side, and that a temporary alteration in the gaseous state of theatmosphere is known to be present. The latter retaining action can alsobe brought about by the aid of other means, that is, by mounting backpressure valves in the tube which in fact allow the liquid to passthrough but prevent it returning.

Another point of the known apparatus consists in the feature that anindication once produced is maintained for several moments. Owing to thegreat danger due to 4 general.

the presence of fire-damp, for example, in

mines, this is very undesirable. If, for example, in consequence of asurge of gasleak-,

ing out of-the bed of coal, which can be removed by the ordinaryventilation, the apparatus 1S operated and indicates such a change n thegaseous state of the atmosphere, it 1s not known whether this change isquite However, an alarm in the whole mine would be very inconvenient ifit were unnecessary. Now according to the invention the diffusionchamber is provided with a passage accessible from the outside, so thatit is possible by momentarily opening and closing this passage to removethe increase or decrease in pressure existing in the diffusion chamber.If it is established many times in succession, that such a change in thegaseous state of the atmosphere has taken place, it must be taken thatthe same exists in the whole space and that danger is reallyapproaching. Since some air with the contaminating gases passes into thediffusion chamber through the opening in the outlet passage device theindication would be prejudiced by this, if the outlet were kept open foran unnecessary long time. I

This disadvantage however can easily be avoided by employing adisplacing apparatus instead of the outlet device, that is to sayforexample, by using a fixed piston which does away with an existingincrease in pressure when drawn out and equalizes a decrease in pressurewhen it is pushed in.

An example of construction according to the present invention isillustrated in the accompanying drawings in which:

Figure 1 shows a communicating system of tubes which is furnished with asiphon tube and Fig. 2 shows a diffusion chamber which is provided withan outlet devio operable from the outside.

In the drawing the porous plate 1 covers the diffusion space 2 from theoutside. One limb of the communicating system of tubes 3 is inconnectionwith the diffusion chamher 2 and the otherlimb is in connection with theatmosphere through the pipe 4. If an increase or decrease in pressure isproduced in the diffusion chamber 2 by reason of the porous plate 1 thenthe liquid in the system of tubes 3 is displaced. According to theinvention, a siphon tube 5 is sealed into the system of tubes 3. If,forexample, owing to a decrease in pressure in the diffusion chamber 2the liquid is pushed up into the right hand limb to such a distance thatit passes over the top of the siphon tube 5, then by the law of siphons,so much liquid is passed into the other limb until the liquid level inthe other tube has reached the end of the siphon tube 5. Thus by thismeans the indicating device is made consit erably more sensitive.

In Fig. 2 the diffusion chamber 2 is provided With a valve 6 which canbe operated from outside bv means of a press button 7. Consequently, ifan increase or decrease or" pressure is set up in the system of tubes 3this indication can be removed and started afresh if the diffusionchamber isplaced in communication With the external air for a moment byopening the valve 6.

Having now particularly described and ascertained the nature of my saidinvention and in What manner the same is to be performed, I declare thatWhat I claim is 1. An apparatus for indicating changes in the gaseouscondition of the atmosphere having a diffusion chamber, a U-shapedbarometric pressure measuring apparatus in communication With saidchamber, and means connecting the two legs of the barometric apparatusto prevent excessive displacement of the liquid therein, together Withmeans for restoring normal pressure to the diffusion chamber.

2. An apparatus of the character described, having a diffusion chamber,a U- shaped barometric pressure measuring apparatus in communicationwith said chamber, and an inverted U-shaped tube c0nnecting the two legsof the barometric apparatus to prevent excessive displacement of theliquid therein.

3. An apparatus for indicating changes in the gaseous condition of theatmosphere having a diflusion chamber, a U-shaped barometric pressuremeasuring apparatus in communication With said chamber, and

means connecting the two legs of the barometric apparatus to preventexcessive displacement of the liquid therein, substantially asdescribed.

4. An apparatus for indicating changes in the gaseous condition of theatmosphere having a diffusion chamber, a U-shaped barometric pressuremeasuring apparatus in communication with said chamber, and a siphontube connecting the two legs of the barometric apparatus to preventexcessive displacement'o'f the liquid therein substantially asdescribed.

In testimony that I claim the foregoing as mv own, I aflix my signaturein presence of two Witnesses.

MARTIN ALBRECHT.

Witnesses: I

FRIEDRICH CARL WENTZEL, MAX HERMANN Horrnnn.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, I). 0.

